1. Technical Field
The disclosure relates to a terminal and a communication method.
2. Description of the Related Art
A method of offloading traffic using a heterogeneous network (HetNet), in which a macro cell and a small cell coexists, has been examined recently. In the heterogeneous network, a small-cell base station, which performs communication with low transmission power, is disposed in an area covered by a macro-cell base station (may be referred to as an eNB or a BS), which performs communication with high transmission power.
In the heterogeneous network, interference from the macro-cell base station occurs in a terminal (may be referred to as user equipment (UE) or a mobile station (MS)) (referred to as an in-small-cell terminal hereinafter) connected to the small-cell base station, in a case where the same carrier frequency is used between the macro cell and the small cell (case of a Co-Channel HetNet). Such inter-cell interference is significant at a cell edge.
In order to prevent the inter-cell interference, suspending transmission of the macro-cell base station during communication in the small cell may be considered. In the macro-cell, however, a terminal (referred to as an in-macro-cell terminal hereinafter) connected to the macro-cell base station also exists outside the area of the small cell. For the in-macro-cell terminal to continue communication, the macro-cell base station is required to continue transmission of a signal (for example, synchronization signal, broadcast channel, and cell-specific reference signal (CRS)) even in a period of suspending transmission of the macro-cell base station (referred to as almost blank subframe (ABS) transmission hereinafter).
Thus, the in-small-cell terminal needs to reduce the interference originating from ABS transmission by the macro-cell base station, in order to improve reception quality of a desired signal. As a conventional interference reduction method, for example, Japanese Patent No. 5383725 and Japanese Patent Unexamined Publication No. 2013-123163 disclose a method of removing an interference component by a terminal generating a replica (referred to as “an interference replica” hereinafter) of an interfering signal from a replica of a transmission signal transmitted by a base station and a channel estimation value, and subtracting the interference replica from a reception signal.